Thomas Huxley Quotes

Inference is always an invasion of the unknown, a leap from the known.

Bad reasoning as well as good reasoning is possible; and this fact is the foundation of the practical side of logic.

In fact the a priori reasoning is so entirely satisfactory to me that if the facts won't fit in, why so much the worse for the facts is my feeling.

Before anything can be reasoned upon to a conclusion, certain facts, principles, or data, to reason from, must be established, admitted, or denied.

Induction for deduction, with a view to construction.

Facts - behind them lies the whole fabric of deductive truth.

Through logic and inference we can prove anything. Therefore, logic and inference, in contrast to ordinary daily living experience, are secondary instruments of knowledge. Probably tertiary.

Without deductive logic science would be entirely useless. It is merely a barren game to ascend from the particular to the general, unless afterwards we can reverse the process and descend from the general to the particular, ascending and descending like angels on Jacob's ladder.

This method of deduction ... is often called "combinatory". Its usefulness is not exhausted at this stage, but it does even at the outset lead to some valuable conclusions.

A theoretical system does not merely state facts which have been observed and that logically deducible relations to other facts which have also been observed.

Reasoning draws a conclusion, but does not make the conclusion certain, unless the mind discovers it by the path of experience.

From principles is derived probability, but truth or certainty is obtained only from facts.

We may either proceed from principles to facts, or recede from facts to principles.

The ideal reasoner, he remarked, would, when he had once been shown a single fact in all its bearings, deduce from it not only all the chain of events which led up to it but also all the results which would follow from it.

Logic can become enormously difficult, and it would undoubtedly be well to produce more assurance in its use.

Pure mathematics consists entirely of assertions to the effect that, if such and such a proposition is true of anything, then suchand such another proposition is true of that thing.... Thus mathematics may be defined as the subject in which we never know what we are talking about, nor whether what we are saying is true.

There is a tradition of opposition between adherents of induction and of deduction. In my view it would be just as sensible for the two ends of a worm to quarrel.

... if you insist that the inference is made by a chain of reasoning, I desire you to produce that reasoning. The connection between the two is not intuitive. There is required a medium, which may enable the mind to draw such an inference, if indeed it be drawn by reasoning and argument. What that medium is, I must confess, passes my comprehension; and it is incumbent on those to produce it, who assert that it really exists, and is the origin of all our conclusions concerning matter of fact.

Scientific method, although in its more refined forms it may seem complicated, is in essence remarkably simply. It consists in observing such facts as will enable the observer to discover general laws governing facts of the kind in question. The two stages, first of observation, and second of inference to a law, are both essential, and each is susceptible of almost indefinite refinement. (1931)

One can't proceed from the informal to the formal by formal means.

A universe whose only claim to be believed in rests on the validity of inference must not start telling us the inference is invalid.

If logic itself is created rather than being inborn, it follows that the first task of education is to form reasoning.

The science of mathematics presents the most brilliant example of how pure reason may successfully enlarge its domain without the aid of experience

Mathematical reasoning may be regarded.

It is not really difficult to construct a series of inferences, each dependent upon its predecessor and each simple in itself. If, after doing so, one simply knocks out all the central inferences and presents one's audience with the starting-point and the conclusion, one may produce a startling, though perhaps a meretricious, effect.